The nuclear reactors currently operating in Canada are known as CANDU (CANada Deuterium Uranium) reactors. These reactors are characterized as Pressurized Heavy Water Reactors (PHWR) that were designed and built by Atomic Energy Canada Ltd since the 1950s.
There are many different kinds of reactor types; and amoung the most common are the Pressurized Water Reactors, Pressurized Heavy Water Reators, Boiling Water Reactors, Gas Cooled Reactors, and a few more.
This chart depicts the break down of reactor types employed in the world.
According to data from 2010, there have been 27 Pressurized Heavy Water Reactors operating worldwide in 6 countries. And 17 of those reactors originate in Canada. These reactors use heavy water,known as D2O, a water formed with the heavier deuterium isotope of hydrogen, as both coolant and moderator.
The advantages of heavy water are that it allows natural uranium to be used as fuel, eliminating the need and cost to enrich the uranium. However, the production of heavy water also requires a dedicated plant to separate the D2O from ordinary water, raising the concentration of D2O from much less than 1% in its natural state, to 99% in a CANDU reactor.
And just like with mainstream Pressurized Water Reactors (PWR), the coolant is passed through a steam generator to boil ordinary water in a separate loop. The advantage of the CANDU design, is that refuelling can take place during operation, whereas PWR’s and Boiling Water Reactors (BWRs) must shut down in order to refuel. The CANDU design feature allows for higher availability, with the trade off in greater complexity.
Here is a diagram of how PHWRs operate
A CANDU fuel bundle is about the size of a regular log that you might use in a fireplace, and when loaded with uranium, it would weigh 24 kilograms. Fuel bundles look the same after they have been used, just as they look when they are placed into the nuclear reactor. However, when the bundles are removed from the reactor, they are highly radioactive and must be managed very carefully for an indefinite period of time.
All of Canada’s nuclear used fuel should be fully managed and accounted for, and is managed in facilities that is licensed by the CNSC. All of the waste is located at the reactors where it is generated. This system allows for changes or improvements to be made along the way, and can take advantage of newer or more advanced techniques when they are developed. Or to adjust if people’s values or priorities change over time. The plan will be phased, implemented in each step before moving to the next.
-The method involves centralized containment of the nuclear waste and isolating it, deep underground in a suitable rock formation. The used fuel will be continuously monitored and retrieved if needed.
Here is a shape of a nuclear fuel rod.
The amount of used fuel rods is around 2 million, equivalent to 6 full sized hockey rinks. Thus, disposal or management of this waste is critical.
For this task, the Nuclear Waste Management Organization (NWMO) was organized by Canada’s Nuclear Electricity Generators in 2002 and they pay the organizations operating costs and contribute to trust funds to make sure the money will be available when it is needed for long term nuclear waste management. After Bill C-27, the
The government passed bill C-27 in 2001, titled the “Nuclear Fuel Waste Act”. This established a nuclear industry- controlled Waste Management Organization (NWMO), with a mandate to review nuclear fuel waste management options. The regulation required the NWMO to consult Canadians all over the country on the subject of nuclear waste management. From 2002 – 2005, the organization engaged over 18,000 citizens and 2,500 Aboriginals in every province and territory. What emerged from this dialogue, was termed Adaptive Phased Management solution for nuclear waste.
As it stands, Canada roughly has 2 million fuel bundles that need to be managed, and about 85,000 used nuclear fuel bundles are generated in Canada each year.
Canada’s energy sources
According to statistics, Canada is the fifth largest electricity producer in the world.
The largest electricity producer is the United States, then China, then Russia, Saudi Arabia, and then Canada. And Canada generates 4 % of the total world production of primary energy , much of which is exported to the United States.
60.1% of Canada’s electricity is generated using hydroelectric dams,
24.7% from the burning of fossil fuels (coal, oil and gas),
14.7% from nuclear power plants
less than 1% from alternative energy sources.
And according to the Canadian Energy Research Initiative, below is a chart on Relative Costs of Electricity Generation:
Solar technology is currently the most expensive “relatively” speaking. Of particular interest is Biomass, Wind, Wave/Tidal, and Geothermal.
Canada’s current energy problem
Canada is characterized as a resource-rich country with vast reserves of commodities such as oil, gas, coal, uranium and many rivers that can still be used for future hydroelectric projects.
However, Hydroelectric dams often require the flooding of large areas of land.
The burning of fossil fuels for transportation and electricity generation emits millions of tonnes of greenhouse gases and other pollutants into the atmosphere
Nuclear power plants produce highly radioactive used fuel which must be managed and stored for hundreds of years
Current alternative energy technologies like wind, solar, tidal and biomass can only meet a fraction of our electrical needs.
Thus this presents a very important challenge in trying to address solutions for Canada’s energy needs. We will attempt to offer alternative solutions in the coming articles.